An automobile vehicle four-stroke internal combustion engine generally includes a block delimiting cylinders defining combustion chambers in each of which is mounted a piston connected to a crankshaft connected via the gearbox to wheels of the automobile vehicle to drive them in rotation. Into each combustion chamber open an intake pipe and an exhaust pipe provided with valves mobile between open and closed positions. The valves are moved between their two positions by camshafts driven by the internal combustion engine. The internal combustion engine also includes a device for feeding the combustion chambers with fuel and an engine control unit connected to the fuel supply device and to the ignition circuit in the case of a controlled ignition engine. Electrical power used on board the vehicle is supplied by an alternator driven by the internal combustion engine and connected to the battery of the vehicle to charge it. The engine is started by a starter motor that is connected to the battery and which has an output gear meshing with a toothed ring fastened to the crankshaft.
It is also known to use a combined alternator/starter motor that provides the alternator and starter motor functions alternately.
The alternator/starter motor when operated as a starter motor provides for fast starting of the engine. When the engine equips an automobile vehicle, it is then possible to envisage stopping the engine temporarily each time that the vehicle is stationary (for example in a traffic jam or at a red light) and to start the engine as soon as the driver indicates their intention to move forward, for example by selecting a gear. When the internal combustion engine is stopped, the actuator immobilizes the valves as quickly as possible in order to reduce the noise associated with movement of the valves, which noise could prove a nuisance when the engine is stopped, at which time the general noise level is relatively low.
However, frequent starting of the engine causes battery charging problems and therefore problems with the rating of the battery.